1. Field of the Invention
The present invention relates to a gearbox for a motorcycle that allows the motorcycle to move backward.
2. Description of the Related Art
A typical motorcycle includes two wheels and cannot move backward. A motorcycle for handicappers or a beach motorcycle includes an engine and a gearbox used in a typical motorcycle and includes at least three wheels. It is not uncommon that a handicapped driver has to get off from his or her motorcycle to push it backward when there is a traffic jam, which is troublesome and inconvenient. The beach motorcycle may be stuck in a larger hole in the sand, which also requires the driver to push it backward. All of these result from failing to provide the backing function.
It is the primary object of the present invention to provide a gearbox for a motorcycle that allows the motorcycle to move backward. Operation of the gearbox is easy and the cost of the gearbox is low.
A gearbox for a motorcycle in accordance with the present invention comprises:
a casing including a compartment;
a gear train including:
an input gear means including a gear shaft rotatably mounted in the compartment and operably connected to and thus driven by an engine of the motorcycle, and
an output gear means including a gear shaft rotatably mounted in the compartment and operably connected to one of at least two wheels of the motorcycle, a first gear and a second gear being rotatably mounted around the gear shaft of the output gear means, a follower block being mounted around the gear shaft of the output gear means and located between the first gear and the second gear, the follower block being slidable along a longitudinal axis of the gear shaft of the output gear means for releasably engaging with one of the first gear and the second gear; and
a control device including a gear lever that is operably connected to move the follower block between a first position and a second position;
wherein when the follower block is in the first position, the follower block is engaged with the first gear such that the gearbox is in a forward gear for moving the motorcycle forward; and
when the follower block is in the second position, the follower block is engaged with the second gear such that the gearbox is in a reverse gear for moving the motorcycle backward.
The follower block is movable to a third position where none of the first gear and the second gear is engaged with the follower block such that the gearbox is in a neutral gear.
A first transmission gear means includes a gear shaft rotatably mounted in the compartment. A third gear, a fourth gear, and a fifth gear are mounted on the gear shaft of the first transmission gear means to rotate therewith, the fourth gear being meshed with the first gear. A second transmission gear means includes a gear shaft rotatably mounted in the compartment. A sixth gear and a seventh gear are mounted to the gear shaft of the second transmission gear means to rotate therewith. The sixth gear is meshed with the fifth gear and the seventh gear is meshed with the second gear. The gear shaft of the input gear means includes an eighth gear provided thereon to rotate therewith, the eighth gear being meshed with the third gear.
The output gear means includes a longitudinal keyway and the follower block includes a longitudinal hole with a longitudinal key for engaging with the longitudinal keyway.
The first gear includes at least one engaging groove defined in a side thereof. The second gear includes at least one engaging groove defined in a side thereof. The follower block includes at least one protrusion on each of two sides thereof for releasable engaging with the engaging groove of the first gear and the engaging groove of the second gear, respectively.
The follower block includes a groove in a side thereof. The control device further comprises a control rod operably connected to the gear lever. The control rod is engaged with the groove of the follower block. Thus, the follower block is movable among the first position, the second position, and the third position upon manual operation on the gear lever.
In an-embodiment of the invention, the control device further comprises a positioning block securely attached to an end of the control rod, the positioning block including three positioning notches that correspond to the first position, the second position, and the third position of the follower block. An engaging block is biased to engage with one of the three positioning notches for retaining the positioning block in place, thereby retaining the control rod and the follower block in place.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.